270 
Spirocliaetoms 
malpigliian tubules of the insects. He concluded that infection might 
result from the insects regurgitating the contents of their alimentary 
canal into the wound in the act of feeding. 
Sergent and Foley (1908) next observed the presence of Pediculus 
vestimenti upon the persons of nearly all patients affected with relapsing 
fever in Sud-Oranais, N. Africa, and they observed spirochaetes in the 
bodies of the lice. Subsequently (1910), they found these lice associated 
with every case they observed in Algeria. 
The most convincing observations are, however, those published in 
a short paper this year by Nicolle, Blaizot and Conseil (1912). They 
note, in respect to its epidemiology, that relapsing fever affords a striking 
similarity to typhus fever. The disease extends in a similar manner, 
it occurs in the same places, when it enters hospitals it does not spread, 
sparing the nurses and physicians who have to deal with the patients 
who have been cleansed, whereas it attacks those who have to handle 
the patients at their entry into the hospital. In both diseases, as 
observed in Tunisia, lice are invariably found on the patients. 
Nicolle and his colleagues obtained negative results when they 
attempted to transmit the disease through the bites of infected lice 
placed upon experimental monkeys and five persons (two of whom were 
the authors), although both men and monkeys were exposed to thousands 
of bites collectively. Upon studying the behaviour of the spirochaetes 
in the lice (P. vestimenti and P. capitis), they found that they dis¬ 
appear and afterwards reappear. But few can be detected in the gut 
five to six hours after the infective feed, and none are discoverable 
microscopically when 24 hours have elapsed. After about eight to 
12 days, however, actively motile spirochaetes reappear in the louse ; at 
first they are short, but later they resemble those seen in the blood. 
Such spirochaetes are observable in lice up to the 11th day, and possibly 
longer. Monkeys inocidated with the contents of lice, crushed on the 
loth day after the infective feed, developed relapsing fever. 
We know that all persons infested with lice are addicted to scratching 
themselves, whereby they excoriate their skin and frequently crush the 
lice upon their bodies. In this manner their hands and finger-nails 
become infected with the body contents of the lice including the 
spirochaetes, and these gain a ready entrance through the excoriated 
skin, thereby infecting the individual. One of the authors, having 
excoriated his skin, smeared the contents of an infected louse upon the 
lesion, and succeeded thereby in infecting bitnself, the disease developing 
after a period of incubation lasting five days. In one experiment. 
